A mining machine and a method for rock excavation

ABSTRACT

A mining machine ( 102 ) for rock excavation, comprising: a rotatable cutting head ( 104 ) having cutting elements ( 108 ); a holder ( 110 ) for holding the cutting head ( 104 ); a movable thrust unit ( 112 ) attached to the holder ( 110 ); a machine body ( 114 ) attached to the thrust unit ( 112 ); a thrust apparatus ( 118 ) for moving the thrust unit ( 112 ) between retracted and extended positions and for pushing the thrust unit ( 112 ) forward, thereby pushing the cutting elements ( 108 ) into a rock formation; a hydraulic pump ( 122 ); a hydraulic consumer ( 125 ); and a hydraulic line system ( 126 ) for connecting the hydraulic pump ( 122 ) to the hydraulic consumer ( 125 ). The hydraulic line system ( 126 ) comprises first hydraulic lines ( 126   a ) attached to the machine body ( 114 ), second hydraulic lines ( 126   b ) attached to the thrust unit ( 112 ), and two telescopic hydraulic line units ( 128 ). Each telescopic hydraulic line unit ( 128 ) connects one ( 126   a ) of the first hydraulic lines ( 126   a ) to one ( 126   b ) of the second hydraulic lines ( 126   b ). The telescopic hydraulic line unit ( 128 ) is retracted and extended with the movement of the thrust unit ( 112 ).

TECHNICAL FIELD

Aspects of the present invention relate to a mining machine for rock excavation. The mining machine comprises a rotatable cutting head having an outer circumferential surface and a plurality of rock engaging cutting elements distributed on the outer circumferential surface, the outer circumferential surface having a width which constitutes the rock cutting width of the cutting head. Further, the mining machine comprises a holder for holding the cutting head, the mining machine being configured to rotate the cutting head in relation to the holder. The mining machine also comprises a thrust unit, which is attached to the holder, and a machine body attached to the thrust unit, the thrust unit being movable in relation to the machine body, wherein the holder is configured to hold the cutting head between the machine body and a rock formation to be excavated. Aspects of the present invention also relate to a method for conveying hydraulic fluid to and from a hydraulic consumer with the aid of a mining machine of the above-mentioned sort. Further, aspects of the present invention relate to a method for rock excavation with the aid of a mining machine of the above-mentioned sort.

BACKGROUND

Instead of fracturing rock and excavating and drilling tunnels or rooms under ground by means of drilling rigs having one or more drilling machines drilling into to a rock formation, or rock, and instead of blasting the rock formation, or rock, mining machines having rotatable cutting heads, such as rotatable cutting wheels having rock-engaging cutters, may be used. The mining machine brings the cutting head or wheel to sweep a meeting rock surface as well as linearly presses the rotating cutting head with high force into the rock formation. Conventionally, the mining machine having a rotatable cutting head is also provided with propelling means for propelling the mining machine in the mine and move the mining machine between different excavation positions or sites. Conventionally, a hydraulic system is used to operate the moving parts of the mining machine. For example, the moving parts of the mining machine may include the rotatable cutting head, a holder for holding the cutting head and the propelling means. The moving parts may be moved by means of hydraulic cylinders and hydraulic motors which are part of the hydraulic system. The transport tunnels and excavation sites of the mine may be limited in size, and parts of the conventional mining machines having a rotatable cutting head may be too bulky and take up much space.

SUMMARY

An object of embodiments of the invention is to provide a solution which mitigates or solves the drawbacks and problems of conventional solutions. The invention is defined by the claims.

According to a first aspect of the invention, the above-mentioned and other objects of the embodiments of present invention are attained by providing a mining machine for rock excavation, the mining machine comprising:

-   -   a rotatable cutting head having an outer circumferential surface         and a plurality of rock-engaging cutting elements distributed on         the outer circumferential surface, the outer circumferential         surface having a width which constitutes the rock cutting width         of the cutting head,     -   a holder for holding the cutting head, the mining machine being         configured to rotate the cutting head in relation to the holder,     -   a thrust unit attached to the holder,     -   a machine body attached to the thrust unit, the thrust unit         being movable in relation to the machine body, wherein the         holder is configured to hold the cutting head between the         machine body and a rock formation to be excavated,     -   a thrust apparatus for moving the thrust unit in relation to the         machine body between a retracted position and an extended         position, the thrust apparatus being configured to push the         thrust unit in a forward direction, thereby pushing the cutting         elements into the rock formation,     -   a hydraulic pump,     -   one or more hydraulic consumers, and     -   a hydraulic line system for hydraulically connecting the         hydraulic pump to the hydraulic consumer.

The hydraulic line system comprises first hydraulic lines attached to the machine body and second hydraulic lines attached to the thrust unit. The hydraulic line system comprises two telescopic hydraulic line units. Each telescopic hydraulic line unit hydraulically connects one of the first hydraulic lines to one of the second hydraulic lines. Each telescopic hydraulic line unit comprises a first tube and a second tube movable in relation to one another. The first tube is configured to telescope into the second tube. One of the first and second tubes is attached to the machine body and the other one of the first and second tubes is attached to the thrust unit. The mining machine, for example by means of the thrust apparatus, is configured to move the thrust unit and the cutting head back and forth in cutting strokes to cut the rock formation, thereby retracting and extending the telescopic hydraulic line unit with the movement of the thrust unit.

A hydraulic consumer is a hydraulic entity or hydraulic actuator that is operated by means of the hydraulic fluid supplied by the hydraulic pump or the hydraulic fluid pressure provided by the hydraulic pump. In general, the hydraulic consumer may in turn control or operate a movable member, for example make the member move in relation to its environment. For example, the hydraulic actuator operated by the hydraulic fluid from the hydraulic pump or by the hydraulic fluid pressure provided by the hydraulic pump may be a hydraulic cylinder or a hydraulic motor, which in turn may control or operate a member, for example a member in the form of an excavating arm or a bucket of an excavator, for example an excavator in the form of an excavating mining machine.

The holder may be called a cutting head holder or a carrying unit. The thrust unit may be indirectly or directly attached or connected to the holder. The holder and the thrust unit may together form one single unit, i.e. the holder may be integral with the thrust unit, or the holder and the thrust unit may be separate parts attached to one another. The machine body may be indirectly or directly attached or connected to the thrust unit. The thrust apparatus may comprise at least one hydraulic cylinder. The front end of the mining machine holds the cutting head. When the thrust unit is pushed or pressed in a forward direction, the thrust unit is pushed in a direction toward the cutting head or in a direction toward the rock formation to be engaged by the rock-engaging cutting elements of the cutting head.

The inventor has found that parts of the conventional hydraulic lines, such as hydraulic conduits or hoses, which hydraulically connect the various hydraulic consumers and the hydraulic pump of the hydraulic system of a conventional mining machine, are too bulky, especially when two units holding hydraulic hoses are movable, for example linearly movable, in relation to each other. Then, an additional hydraulic hose length is needed to compensate for the movement between the two units holding the hydraulic hoses. This additional hydraulic hose length must be carried and stored by the movable mining machine when the two units holding hydraulic hoses are adjacent to one another, which makes the conventional hydraulic system of the mining machine bulky. For example, one reason is that a hydraulic hose with dimensions applicable to a mining machine having a rotatable cutting head cannot be bent or curved too much. An advantage of the mining machine according to the first aspect is that the bulky additional hydraulic hose length can be excluded as a result of the innovative hydraulic line system including the telescopic hydraulic line units of the mining machine according to the first aspect. Thus, the mining machine according to the first aspect is more compact or can be made more compact. Further, the moving conventional additional hydraulic hose length is subjected to wear, when the two units holding the hydraulic hoses are moving in relation to one another. Thus, an advantage of the mining machine according to the first aspect is that the wear on the hydraulic lines or hoses is reduced, whereby a more robust hydraulic system of the mining machine is provided. An additional advantage of the mining machine according to the first aspect is that longer cutting strokes back and forth can be performed by the thrust unit and the cutting head, i.e. the cutting stroke length of the thrust unit and the cutting head can be extended, because conventional bulky hydraulic conduits or hoses can be excluded by way of the innovative arrangement of the telescopic hydraulic line units and thus will not hinder or block the cutting strokes back and forth. Thus, according to the mining machine of the first aspect, a more robust and durable mining machine subjected to less wear is provided. Consequently, the excavation performed by the mining machine having a rotatable cutting head is improved by means of the mining machine according to the first aspect.

According to embodiments of the mining machine according to the first aspect, in addition to the first and second tubes, the telescopic hydraulic line unit may comprise one or more additional tubes movable in relation to one another and movable in relation to the first and second tubes. Each additional tube is configured to telescope with one or more other tubes, i.e. to telescope into one or more other tubes and/or to be telescoped or entered by one or more other tubes. Consequently, each of the first and second tubes may telescope with one or more additional tubes, i.e. to telescope into one or more additional tubes and/or to be telescoped or entered by one or more additional tubes. Thus, the telescopic hydraulic line unit may comprise three, four, five or more telescoping tubes, which are thus movable in relation to one another.

According to an advantageous embodiment of the mining machine according to the first aspect, each telescopic hydraulic line unit forms a hydraulic channel, wherein each hydraulic channel is hydraulically connected to one of the first hydraulic lines by means of a first hydraulic block having hydraulic channels, and wherein each hydraulic channel is hydraulically connected to one of the second hydraulic lines by means of a second hydraulic block having hydraulic channels. An advantage of this embodiment is that an efficient connection of the telescopic hydraulic line units to the first and second hydraulic lines is provided, whereby a robust hydraulic system of the mining machine is provided. Therefore, the excavation performed by the mining machine is further improved.

According to a further advantageous embodiment of the mining machine according to the first aspect, the mining machine comprises one or more propelling units for propelling the mining machine, wherein the propelling unit is configured to rest on a floor of a tunnel during the rock excavation.

According to another advantageous embodiment of the mining machine according to the first aspect, the mining machine comprises one or more first stabilizing units movable in relation to the machine body, wherein the first stabilizing unit is configured to engage a roof of a tunnel to secure the mining machine and counteract forces created during the rock excavation. An advantage of this embodiment is that a controlled and efficient excavation performed by the mining machine is provided.

According to yet another advantageous embodiment of the mining machine according to the first aspect, the mining machine comprises one or more second stabilizing units movable in relation to the machine body and configured to engage a floor of the tunnel to secure the mining machine and counteract forces created during the rock excavation. An advantage of this embodiment is that a controlled and efficient excavation performed by the mining machine is provided.

According to still another advantageous embodiment of the mining machine according to the first aspect, at least one of the first stabilizing unit and the second stabilizing unit is attached to the machine body. An advantage of this embodiment is that a controlled and efficient excavation performed by the mining machine is provided.

According to an advantageous embodiment of the mining machine according to the first aspect, the hydraulic consumer or one of the hydraulic consumers is attached to the cutting head. A plurality of the hydraulic consumers may be attached to the cutting head.

According to a further advantageous embodiment of the mining machine according to the first aspect, the hydraulic consumer or one of the hydraulic consumers is attached to the holder. A plurality of the hydraulic consumers may be attached to the holder.

According to another advantageous embodiment of the mining machine according to the first aspect, the mining machine comprises one or more hydraulic motors for rotating the cutting head in relation to the holder, the hydraulic motor comprising the hydraulic consumer or one of the hydraulic consumers. An advantage of this embodiment is that a controlled and efficient excavation executed by the mining machine is provided. The hydraulic motor may be attached to the cutting head and/or to the holder. The hydraulic motor may be located in the centre of the cutting head, for example close to or at the axis of rotation of the cutting head. The mining machine may comprise a plurality of hydraulic motors for rotating the cutting head in relation to the holder, each hydraulic motor comprising one of the hydraulic consumers. There may also be a gearbox, a variable gear or a variable transmission between each hydraulic motor and the cutting head.

According to still another advantageous embodiment of the mining machine according to the first aspect, the hydraulic consumer or one of the hydraulic consumers is attached to the thrust unit. A plurality of the hydraulic consumers may be attached to the thrust unit.

According to an advantageous embodiment of the mining machine according to the first aspect, the mining machine comprises one or more guide apparatuses for guiding the thrust unit in relation to the machine body between the retracted position and the extended position, each guide apparatus comprising a guide. An advantage of this embodiment is that a controlled and efficient movement of the thrust unit in relation to the machine body is provided.

According to a further advantageous embodiment of the mining machine according to the first aspect, the guide is substantially linear, wherein the guide apparatus is configured to linearly move the thrust unit in relation to the machine body between the retracted position and the extended position. An advantage of this embodiment is that a controlled and efficient movement of the thrust unit in relation to the machine body is provided.

According to another advantageous embodiment of the mining machine according to the first aspect, the holder is movable in relation to the thrust unit, wherein the mining machine comprises a positioning apparatus for moving and positioning the holder and the cutting head in relation to the thrust unit in a horizontal direction and/or a vertical direction when the propelling unit rests on the floor of the tunnel. An advantage of this embodiment is that the holder can be moved and positioned in an efficient manner.

According to still another advantageous embodiment of the mining machine according to the first aspect, each cutting element comprises a disc-shaped cutter, wherein the cutting head comprises a cutting head frame having a cutter seat for each cutter, and wherein the cutter is seated in the cutter seat and is rotatable in relation to the cutting head frame. An advantage of this embodiment is that an efficient excavation performed by the mining machine is provided. The distance between two neighbouring disc-shaped cutters in a direction parallel to the axis of rotation of the cutting head may be set or adjusted based on the rock to be cut, for example based on the type of rock, the structure of the rock, the condition of the rock etc. Said axial distance between two neighbouring cutters is set such that cracks, which extend from a cut or groove, for example a vertical groove, cut by the cutters to a neighbouring cut or groove, for example a vertical groove, cut by the cutters, are formed when the cutting head is rotating, which facilitates the rock excavation. However, other rock cutting processes may be executed or performed by the mining machine according to the first aspect.

According to yet another advantageous embodiment of the mining machine according to the first aspect, the cutting head has a first side between the outer circumferential surface and an axis of rotation of the cutting head and a second side between the outer circumferential surface and the axis of rotation of the cutting head, wherein the holder comprises a first arm extending at least partly along the first side and holding the cutting head, whereas the second side of the cutting head is without any such arm, or free from such an arm or support structure. An advantage of this embodiment and the one-sided holder is that an efficient excavation performed by the mining machine is provided.

According to an advantageous embodiment of the mining machine according to the first aspect, the hydraulic pump is attached to the machine body.

According to a further advantageous embodiment of the mining machine according to the first aspect, the mining machine comprises a first part and a second part, wherein the first part comprises the cutting head, the holder, the thrust unit and the machine body, wherein the second part comprises the hydraulic pump, and wherein the first and second parts are connectable, or attachable, attached or connected, to one another. An advantage of this embodiment is that an efficient excavation performed by the mining machine is provided.

According to another advantageous embodiment of the mining machine according to the first aspect, at least one of the first and second the stabilizing units is configured to secure the first part to counteract forces on the first part created during the rock excavation. An advantage of this embodiment is that a controlled and efficient excavation executed by the mining machine is provided.

According to still another advantageous embodiment of the mining machine according to the first aspect, the second part comprises control equipment for controlling the mining machine. Thus, the control equipment can be installed with a distance to the rock-cutting region, i.e. the region where the cutting elements of the cutting head cut or engage the rock or rock formation. An advantage of this embodiment is that an efficient excavation performed by the mining machine is provided.

According to yet another advantageous embodiment of the mining machine according to the first aspect, the mining machine comprises an operator cabin attached to the second part of the mining machine, and wherein the mining machine is controllable from the operator cabin. Thus, the operator cabin can be situated with a distance to the rock-cutting region. An advantage of this embodiment is that an efficient excavation performed by the mining machine is provided.

According to an advantageous embodiment of the mining machine according to the first aspect, the mining machine is controllable from a remote location. An advantage of this embodiment is that an efficient excavation performed by the mining machine is provided.

According to a further advantageous embodiment of the mining machine according to the first aspect, the mining machine is configured to operate at least partly autonomously. An advantage of this embodiment is that an efficient excavation performed by the mining machine is provided.

According to a second aspect of the invention, the above-mentioned and other objects of the embodiments of present invention are attained by providing a method for conveying hydraulic fluid to and from a hydraulic consumer with the aid of a mining machine comprising:

-   -   a rotatable cutting head having an outer circumferential surface         and a plurality of rock-engaging cutting elements distributed on         the outer circumferential surface, the outer circumferential         surface having a width which constitutes the rock cutting width         of the cutting head,     -   a holder for holding the cutting head, the mining machine being         configured to rotate the cutting head in relation to the holder,     -   a thrust unit attached to the holder,     -   a machine body attached to the thrust unit, the thrust unit         being movable in relation to the machine body, wherein the         holder is configured to hold the cutting head between the         machine body and a rock formation to be excavated,     -   a thrust apparatus for moving the thrust unit in relation to the         machine body between a retracted position and an extended         position, the thrust apparatus being configured to push the         thrust unit in a forward direction, thereby pushing the cutting         elements into the rock formation,     -   a hydraulic pump,     -   the hydraulic consumer, and     -   a hydraulic line system for hydraulically connecting the         hydraulic pump to the hydraulic consumer.

The hydraulic line system comprises first hydraulic lines attached to the machine body and second hydraulic lines attached to the thrust unit. The hydraulic line system comprises two telescopic hydraulic line units. Each telescopic hydraulic line unit hydraulically connects one of the first hydraulic lines to one of the second hydraulic lines. Each telescopic hydraulic line unit comprises a first tube and a second tube movable in relation to one another. The first tube is configured to telescope into the second tube. One of the first and second tubes is attached to the machine body and the other one of the first and second tubes is attached to the thrust unit. The mining machine is configured to move the thrust unit and the cutting head back and forth in cutting strokes to cut the rock formation, thereby retracting and extending the telescopic hydraulic line unit with the movement of the thrust unit. The method of the second aspect comprises:

-   -   Conveying hydraulic fluid from the hydraulic pump to the         hydraulic consumer by means of the hydraulic line system and the         telescopic hydraulic line units; and     -   Conveying hydraulic fluid from the hydraulic consumer to the         hydraulic pump by means of the hydraulic line system and the         telescopic hydraulic line units.

The advantages of the method according to the second aspect correspond to the advantages and positive effects mentioned above in connection with the mining machine according to the first aspect.

According to a third aspect of the invention, the above-mentioned and other objects of the embodiments of present invention are attained by providing a method for rock excavation with the aid of a mining machine comprising:

-   -   a rotatable cutting head having an outer circumferential surface         and a plurality of rock-engaging cutting elements distributed on         the outer circumferential surface, the outer circumferential         surface having a width which constitutes the rock cutting width         of the cutting head,     -   a holder for holding the cutting head, the cutting head being         rotatable in relation to the holder,     -   a thrust unit attached to the holder,     -   a machine body attached to the thrust unit, the thrust unit         being movable in relation to the machine body, wherein the         holder is configured to hold the cutting head between the         machine body and a rock formation to be excavated,     -   a thrust apparatus for moving the thrust unit in relation to the         machine body between a retracted position and an extended         position, the thrust apparatus being configured to push the         thrust unit in a forward direction, thereby pushing the cutting         elements into the rock formation,     -   a hydraulic pump,     -   one or more hydraulic consumers, and     -   a hydraulic line system for hydraulically connecting the         hydraulic pump to the hydraulic consumer.

The hydraulic line system comprises first hydraulic lines attached to the machine body and second hydraulic lines attached to the thrust unit. The hydraulic line system comprises two telescopic hydraulic line units, wherein each telescopic hydraulic line unit hydraulically connects one of the first hydraulic lines to one of the second hydraulic lines. Each telescopic hydraulic line unit comprises a first tube and a second tube movable in relation to one another, wherein the first tube is configured to telescope into the second tube. One of the first and second tubes is attached to the machine body and the other one of the first and second tubes is attached to the thrust unit. The mining machine is configured to move the thrust unit and the cutting head back and forth in cutting strokes to cut the rock formation, thereby retracting and extending the telescopic hydraulic line unit with the movement of the thrust unit. The method of the third aspect comprises:

-   -   Pushing the thrust unit in a forward direction by means of the         thrust apparatus, thereby pushing the cutting elements of the         cutting head into the rock formation;     -   Conveying hydraulic fluid from the hydraulic pump to the         hydraulic consumer, which is a hydraulic motor for rotating the         cutting head in relation to the holder, by means of the         hydraulic line system and the telescopic hydraulic line units;     -   Conveying hydraulic fluid from the hydraulic consumer to the         hydraulic pump by means of the hydraulic line system and the         telescopic hydraulic line units; and     -   Rotating the cutting head by means of the hydraulic motor.

The advantages of the method according to the third aspect correspond to the advantages and positive effects mentioned above in connection with the mining machine according to the first aspect.

The above-mentioned features and embodiments of the mining machine and the method, respectively, may be combined in various possible ways providing further advantageous embodiments.

Further advantageous embodiments of the present invention and further advantages with the embodiments of the present invention emerge from the dependent claims and the detailed description of embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present invention will now be described, for exemplary purposes, in more detail by way of embodiments and with reference to the enclosed drawings, in which:

FIG. 1 is a schematic side view of an embodiment of the mining machine according to the first aspect;

FIG. 2 is a side view of the mining machine of FIG. 1 where some parts are at least partly transparent to illustrate the hydraulic system of the mining machine;

FIG. 3 is a schematic top view of the mining machine of FIG. 1;

FIG. 4 is a top view of the mining machine of FIG. 3 where some parts are at least partly transparent to illustrate the hydraulic system of the mining machine;

FIG. 5 is a schematic perspective view of the front of the mining machine of FIG. 1;

FIG. 6 is a schematic cutaway perspective view of the front of the mining machine of FIG. 1 with the thrust unit in an extended position, where some parts are at least partly transparent to illustrate the hydraulic system of the mining machine;

FIG. 7 is a schematic cutaway perspective view of the front of the mining machine shown in FIG. 6, but with the thrust unit in a retraced position, where some parts are at least partly transparent to illustrate the hydraulic system of the mining machine;

FIG. 8 is a schematic cutaway perspective view of the front of the mining machine of FIG. 1 with the thrust unit in an extended position;

FIG. 9 is an enlargement of the telescopic hydraulic line units of FIG. 8 when the thrust unit is in the extended position;

FIG. 10 is a schematic cutaway perspective view of the front of the mining machine of FIG. 1 with the thrust unit in a retracted position;

FIG. 11 is an enlargement of the telescopic hydraulic line units of FIG. 10 when the thrust unit is in the retracted position;

FIG. 12 is a schematic cutaway side view of the cutting head of the mining machine of FIG. 1 seen from the side of the cutting head which is free from a holder arm;

FIG. 13 is a schematic cutaway side view of the cutting head of the mining machine of FIG. 1 seen from the side of the cutting head which has a holder arm;

FIG. 14 is a flow chart illustrating an embodiment of the method according to the second aspect of the present invention; and

FIG. 15 is a flow chart illustrating an embodiment of the method according to the third aspect of the present invention.

DETAILED DESCRIPTION

With reference to FIGS. 1 and 3, a mining machine 102 for rock excavation and/or driving tunnels, galleries, shafts or the like, is schematically shown. The mining machine 102 may comprise a first part 154, which may be called a front part or a front unit, and a second part 156, which may be called a rear part or rear unit. The first and second parts 154, 156 are connectable to one another via connection apparatus 157 or a connection section 157. The mining machine 102 has one or more propelling units 131, 134 for propelling the mining machine 102, for example between different excavation sites or positions. In the embodiment shown in FIG. 1, the first part 154 of the mining machine 102 is carried by front propelling units 131, for example crawler bands, of the propelling units 131, 134, whereas the second part 156 of the mining machine 102 is carried by rear propelling units 134, for example crawler bands, of the propelling units 131, 134. At the front of the second part 156 of the mining machine 102, the second part 156 is also carried by the first part 154 of the mining machine 102 via the connection section 157. Each propelling unit 131, 134 is configured to rest on a floor of a tunnel during the rock excavation.

With reference to FIGS. 1 and 3, the mining machine 102 includes a rotatable cutting head 104 having an outer circumferential surface 106 and a plurality of rock-engaging cutting elements 108 distributed on the outer circumferential surface 106. The outer circumferential surface 106 has a width 107 which constitutes the rock cutting width 107 of the cutting head 104. With reference to FIGS. 1, 3 and 5, the mining machine 102 includes a holder 110 for holding the cutting head 104. The mining machine 102 is configured to rotate the cutting head 104 in relation to the holder 110 about an axis of rotation 111 of the cutting head 104, which may be substantially parallel to the ground or floor on which the mining machine 102 rests.

With reference to FIGS. 6 and 8, the mining machine 102 includes a thrust unit 112 attached to the holder 110. The thrust unit 112 may be a thrust frame. Further, the mining machine 102 has machine body 114 attached to the thrust unit 112. The thrust unit 112 is movable in relation to the machine body 114. With reference to FIGS. 3, 6 and 8, the holder 110 is configured to hold the cutting head 104 between the machine body 114 and a rock formation 115, or rock 115, to be excavated, i.e. the holder 110 is configured to hold the cutting head 104 at the front of the mining machine 102, for example at the front of the first part 154 of the mining machine 102. More precisely, the holder 110 is configured to hold the cutting head 104 between the thrust unit 112 and the rock formation to be excavated. Thus, the holder 110 is configured to hold the cutting head 104 in front of the thrust unit 112.

With reference to FIGS. 8 and 10, the mining machine 102 also includes a thrust apparatus 118, for example a hydraulic cylinder, for moving the thrust unit 112 in relation to the machine body 114 between a retracted position, which is shown in FIGS. 7, 10 and 11, and an extended position, which is shown in FIGS. 6, 8 and 9. Thus, the thrust apparatus 118 is configured to move the thrust unit 112 in relation to the machine body 114 in a forward direction 119, to the extended position, and the thrust apparatus 118 is configured to move the thrust unit 112 in relation to the machine body 114 in a backward direction 123 to the retracted position. The thrust apparatus 118 is configured to push the thrust unit 112 in the forward direction 119, thereby pushing the cutting elements 108 into the rock formation 115, whereupon the cutting head 104 is rotated to excavate rock. The first part 154 of the mining machine 102 includes the cutting head 104, the holder 110, the thrust unit 112 and the machine body 114. With reference to FIG. 5, the mining machine 102 may include a casing 155 which covers the thrust unit 112 and the machine body 114.

With reference to FIGS. 2 and 4, the mining machine 102 includes a hydraulic pump 122. The hydraulic pump 122 may include a hydraulic fluid reservoir. With reference to FIG. 2, the mining machine 102 has one or more hydraulic consumers 125 and a hydraulic line system 126 for hydraulically connecting the hydraulic pump 122 to each hydraulic consumer 125. “Hydraulically connecting” in this context means that there is a hydraulic connection between the hydraulic pump 122 and the hydraulic consumer 125. The hydraulic pump 122, the hydraulic consumer 125 or consumers 125 and the hydraulic line system 126 together form a group of equipment which may be called the hydraulic system of the mining machine 102. The second part 156 of the mining machine 102 comprises or carries the hydraulic pump 122.

With reference to FIGS. 2, 12 and 13, the mining machine 102 comprises a hydraulic motor 136, or a plurality of hydraulic motors, for rotating the cutting head 104 in relation to the holder 110. The hydraulic motor 136 includes the hydraulic consumer 125 or one 125 of the hydraulic consumers 125. In the embodiment shown in FIGS. 2, 12, 13, the hydraulic consumer 125, and thus also the hydraulic motor 136, includes a plurality, i.e. two or more, of hydraulic connections 124 or hydraulic connection elements 124, for example one hydraulic inlet connection 124 and one hydraulic outlet connection 124, which are connected to the hydraulic line system 126. One 125 or more of the hydraulic consumers 125 are attached to the holder 110. One or more of the hydraulic consumers may be attached to the cutting head 104. In alternative embodiments, one or more of the hydraulic consumers may be attached to the thrust unit 112. The hydraulic motor 136 may be called a hydraulic rotation motor 136. The hydraulic motor 136 may be located inside the cutting head 104.

With reference to FIGS. 2 and 4, the hydraulic line system 126 includes first hydraulic lines 126 a attached to the machine body 114. The hydraulic line system 126 includes second hydraulic lines 126 b attached to the thrust unit 112. The first and second hydraulic lines 126 a, 126 b may be hydraulic hoses. With reference to FIGS. 2, 4, 6 and 7, the hydraulic line system 126 also includes two or more telescopic hydraulic line units 128. In the shown embodiment, the hydraulic line system 126 has four telescopic hydraulic line units 128, but two may be enough. Each telescopic hydraulic line unit 128 hydraulically connects one 126 a of the first hydraulic lines 126 a to one 126 b of the second hydraulic lines 126 b. “Hydraulically connects” in this context means that a hydraulic connection is provided between one 126 a of the first hydraulic lines 126 a and one 126 b of the second hydraulic lines 126 b. The telescopic line unit 128 may be called a telescopic hydraulic cylinder. The first hydraulic lines 126 a of the machine body 114 hydraulically connect the hydraulic pump 122 to the telescopic hydraulic line units 128. The second hydraulic lines 126 b of the thrust unit 112 hydraulically connect the hydraulic consumer 125 to the telescopic hydraulic line units 128.

With reference to FIGS. 8 to 11, each telescopic hydraulic line unit 128 includes a first tube 130 and a second tube 132 movable in relation to one another, wherein the first tube 130 is configured to telescope into the second tube 132. The first tube 130 may be called an inner tube, and the second tube 132 may be called an outer tube. One or more sealings may be provided between the first tube 130 and the second tube 132, for example an O-ring. One 130, 132 of the first and second tubes 130, 132 is attached to the machine body 114 and the other one 130, 132 of the first and second tubes 130, 132 is attached to the thrust unit 112. In the shown embodiment, the first, or inner, tube 130 is attached to the thrust unit 112, and the second, or outer, tube 132 is attached to the machine body 114. The mining machine 102 is configured to move the thrust unit 112 and the cutting head 104 back and forth in cutting strokes to cut the rock formation 115, thereby retracting and extending each telescopic hydraulic line unit 128 with the movement of the thrust unit 112. In FIGS. 6, 8 and 9, each telescopic hydraulic line unit 128 is an extended state, whereas in FIGS. 7, 10 and 11 each telescopic hydraulic line unit 128 is in a retracted state. When the telescopic hydraulic line unit 128 is an extended state, the thrust unit 112 is in an extended position. When each telescopic hydraulic line unit 128 is in a retracted state, the thrust unit 112 is in a retracted position.

With reference to FIG. 2 and FIGS. 8 to 11, each telescopic hydraulic line unit 128 forms a hydraulic channel 133, and each hydraulic channel 133 is hydraulically connected to one 126 a of the first hydraulic lines 126 a by means of a first hydraulic block 135 having hydraulic channels. Each hydraulic channel 133 is also hydraulically connected to one 126 b of the second hydraulic lines 126 b by means of a second hydraulic block 137 having hydraulic channels. “Hydraulically connected” in this context means that there is a hydraulic connection between the respective hydraulic channel 133 and the respective hydraulic line 126 a, 126 b. The first hydraulic block 135 may be fixedly attached to the machine body 114. The second hydraulic block 137 may be fixedly attached to the thrust unit 112. Alternatively, the second hydraulic block 137 may be flexibly attached to the thrust unit 112, for example by means of a biasing apparatus, for example including one or more gaskets, for example in rubber, or one or more springs, or by means of a joint coupling or a universal joint. In the same manner, the first hydraulic block 135 may be flexibly attached to the machine body 114. To have the first hydraulic block 135 and/or the second hydraulic block 137 flexibly attached will allow the design to handle relative, side-to-side or up and down, movements between the machine body 114 and the thrust unit 112 without the risk of damaging the telescopic hydraulic connection. Thus, by having the attachment of the telescopic hoses flexibly attached to the machine body 114 and/or the thrust unit 112, the design can handle a certain variation in angle between the attachments points without the risk of damaging or increasing the wear of the telescopic hoses or their attachments. In the shown embodiment, the first tube 130 is fixedly attached to the second hydraulic block 137, and the second tube 132 is fixedly attached to the first hydraulic block 135. In an alternative embodiment, each hydraulic channel 133 may be hydraulically connected directly to one 126 a of the first hydraulic lines 126 a and directly to one 126 b of the second hydraulic lines 126 b, and thus excluding the first and second hydraulic blocks 135, 137.

With reference to FIGS. 1 and 2, the mining machine 102 includes one or more first stabilizing units 120 movable in relation to the machine body 114. Each first stabilizing unit 120 is configured to engage a roof of a tunnel to secure the mining machine 102 and counteract forces created during the rock excavation. Each first stabilizing unit 120 may include a hydraulic cylinder. The mining machine 102 also includes one or more second stabilizing units 121 movable in relation to the machine body 114 and configured to engage a floor of the tunnel to secure the mining machine 102 and counteract forces created during the rock excavation. In the shown embodiment, the mining machine 102 includes two second stabilizing units 120, one on each side of a longitudinal central axis of the mining machine 102. Each second stabilizing unit 121 may include a hydraulic cylinder. In FIGS. 1 and 2, all stabilizing units 120, 121 are in a retracted and inactive position, which is the position for the stabilizing units 120, 121 when propelling the mining machine 102, for example to a new excavation site or position. In the shown embodiment, the first stabilizing units 120 and the second stabilizing unit 121 are attached to the machine body 114. The first and second the stabilizing units 120, 121 may be configured to secure the first part 154 of the mining machine 102 to counteract forces on the first part 154 created during the rock excavation.

With reference to FIGS. 6 and 7, the mining machine 102 has one or more guide apparatuses 117 for guiding the thrust unit 112 in relation to the machine body 114 between the retracted position and the extended position. In the shown embodiment, the mining machine 102 has two guide apparatuses 117. Each guide apparatus 117 includes a guide 127, for example in form of a circular cylinder, and a guide member 129, for example a cuff, which is in engagement with the guide 127. The guide member 129 is movable in relation to the guide 127. The guide 127 is mounted to one 114 of the thrust unit 112 and the machine body 114 and the guide member 129 is attached to the other one 112 of the of the thrust unit 112 and the machine body 114. In the shown embodiment, the guide 127 is mounted to the machine body 114, and the guide member 129 is attached to the thrust unit 112. The guide 127 is substantially linear, wherein the guide apparatus 117 is configured to linearly move the thrust unit 112 in relation to the machine body 114 between the retracted position and the extended position. The linear guide 127 is configured to extend substantially parallel to the floor on which the mining machine 102 rests.

With reference to FIGS. 6 and 7, the holder 110 is movable in relation to the thrust unit 112. The mining machine 102 includes a positioning apparatus 138 for moving and positioning the holder 110 and the cutting head 104 in relation to the thrust unit 112 in a horizontal direction and/or a vertical direction when the propelling units 131, 134 rest on the ground or floor of the tunnel. The positioning apparatus 138 comprises a plurality of hydraulic cylinders 139. In the shown embodiment, the positioning apparatus 138 includes three hydraulic cylinders 139. Each hydraulic cylinder 139 is pivotally attached to the thrust unit 112 and pivotally attached to the holder 110.

With reference to FIG. 10, each cutting element 108 comprises a disc-shaped cutter 140. The cutting head 104 includes a cutting head frame 142 having a cutter seat 144 for each cutter 140. The cutter 140 is seated in the cutter seat 144 and is rotatable in relation to the cutting head frame 142.

With reference to FIGS. 3 and 5, the cutting head 104 has a first side 146 between the outer circumferential surface 106 and the axis of rotation 111 of the cutting head 104. Further, the cutting head 104 has a second side 150 between the outer circumferential surface 106 and the axis of rotation 111 of the cutting head 104. The holder 110 has a first arm 152 extending at least partly along the first side 146 and holding the cutting head 104, whereas the second side 150 of the cutting head 104 is without or free from any such arm.

With reference to FIG. 1, the second part 156 of the mining machine 102 includes control equipment 148 for controlling the mining machine 102. Further, the mining machine 102 has an operator cabin 158 attached to the second part 156 of the mining machine 102, and the mining machine 102 is controllable from the operator cabin 158. Further, the mining machine 102 may be controllable from a remote location. The mining machine 102 is configured to operate at least partly autonomously.

The excavation process by means of the mining machine 102 as disclosed above can be performed as follows. With reference to FIGS. 6 to 11, the thrust apparatus 118 is configured to move the thrust unit 112 from the retracted position, which is shown in FIGS. 7, 10 and 11, to the extended position, which is shown in FIGS. 6, 8 and 9, thereby moving the cutting head 104 forward 119 and pushing the cutting elements 108 of the cutting head 104 with high force into the rock formation 115, whereupon the mining machine 102 is configured to rotate the cutting head 104 in relation to the holder 110, whereby vertical grooves are cut by the cutting elements 108, and cracks, which extend from a vertical groove cut by cutting elements 108 to a neighbouring vertical groove cut by other cutting elements 108, are formed, whereby rock is cut from the rock formation 115. When the cutting elements 108 are pushed into the rock formation 115 and the cutting head 104 is rotating, the rotating cutting head 104 may also be moved upwards or downwards by the positioning apparatus 138 in a direction essentially perpendicular to the axis of rotation 111 of the cutting head 104. When moving the cutting head 104 to the next cutting position or region, the thrust apparatus 118 is configured to move the thrust unit 112 from the extended position, which is shown in FIGS. 6, 8 and 9, to the retracted position, which is shown FIGS. 7, 10 and 11, thereby moving the cutting head 104 backward 123, whereupon the cutting head 104 is released from its engagement with the rock formation 115. Subsequently, the positioning apparatus 138 is configured to laterally move the holder 110 and the cutting head 104 in relation to the thrust unit 112 in a horizontal direction, i.e. the holder 110 and the cutting head 104 are moved by the positioning apparatus 138 to a new cutting position or region just beside the previous cutting position. Then, the thrust apparatus 118 is configured to move the thrust unit 112 from the retracted position (shown FIGS. 7, 10 and 11) to the extended position (shown in FIGS. 6, 8 and 9), thereby moving the cutting head 104 forward 119 and pushing the cutting elements 108 of the cutting head 104 into the rock formation 115 at the new cutting position, whereupon the mining machine 102 is configured to rotate the cutting head 104 in relation to the holder 110, whereby rock is cut from the rock formation 115. This sequence is repeated until a sufficient rock volume has been cut or excavated at the location where the mining machine 102 is presently parked.

With reference to FIG. 14, an embodiment of the method for conveying hydraulic fluid to and from a hydraulic consumer 125 with the aid of a mining machine 102 according to any one of the above-mentioned embodiments is schematically illustrated in a flow chart. The method of FIG. 14 comprises conveying 301 hydraulic fluid from the hydraulic pump 122 to the hydraulic consumer 125 by means of the hydraulic line system 126 and the telescopic hydraulic line units 128. Further, the method of FIG. 14 comprises conveying 302 hydraulic fluid from the hydraulic consumer 125 to the hydraulic pump 122 by means of the hydraulic line system 126 and the telescopic hydraulic line units 128.

With reference to FIG. 15, an embodiment of the method for rock excavation with the aid of a mining machine 102 according to any one of the above-mentioned embodiments is schematically illustrated in a flow chart. The method of FIG. 15 comprises:

-   -   Pushing 401 the thrust unit 112 in a forward direction by means         of the thrust apparatus 118, thereby pushing the cutting         elements 108 of the cutting head 104 into the rock formation;     -   Conveying 402, or deliver, hydraulic fluid from the hydraulic         pump 122 to the hydraulic consumer 125, which is a hydraulic         motor 136 for rotating the cutting head 104 in relation to the         holder 110, by means of the hydraulic line system 126 and the         telescopic hydraulic line units 128;     -   Conveying 403, or deliver, hydraulic fluid from the hydraulic         consumer 125 to the hydraulic pump 122 by means of the hydraulic         line system 126 and the telescopic hydraulic line units 128; and     -   Rotating 404 the cutting head 104 by means of the hydraulic         motor 136.

The method for rock excavation with the aid of a mining machine 102 may also include the step of moving the thrust unit 112 in a backward direction to disengage the cutting head 104 from the rock formation in order to move the cutting head 104 to a new cutting region.

The invention shall not be considered limited to the embodiments illustrated, but can be modified and altered in many ways by one skilled in the art, without departing from the scope of the appended claims, which define the invention. 

1. A mining machine for rock excavation, the mining machine comprising a machine body, a rotatable cutting head, a holder for holding the rotatable cutting head, a thrust unit attached to the holder, and a thrust apparatus for moving the thrust unit in relation to the machine body; the mining machine further comprising: a hydraulic pump, one or more hydraulic consumers, and a hydraulic line system for hydraulically connecting the hydraulic pump to the hydraulic consumer, wherein the hydraulic line system comprises two telescopic hydraulic line units, wherein each telescopic hydraulic line unit hydraulically connects one of first hydraulic lines attached to the machine body to one of second hydraulic lines attached to the thrust unit, characterized in, that each telescopic hydraulic line unit comprises a first tube and a second tube movable in relation to one another, wherein the first tube is configured to telescope into the second tube, and wherein one of the first and second tubes is attached to the machine body and the other one of the first and second tubes is attached to the thrust unit, and that the mining machine is configured to move the thrust unit and the cutting head back and forth in cutting strokes to cut the rock formation, thereby retracting and extending the telescopic hydraulic line unit with the movement of the thrust unit.
 2. A mining machine according to claim 1, the mining machine being configured to rotate the cutting head in relation to the holder, the holder being configured to hold the cutting head between the machine body and a rock formation to be excavated, the rotatable cutting head having an outer circumferential surface and with a plurality of rock-engaging cutting elements distributed on the outer circumferential surface, the outer circumferential surface having a width which constitutes the rock cutting width of the cutting head, and the thrust unit being movable in relation to the machine body between a retracted position and an extended position, the thrust apparatus being configured to push the thrust unit in a forward direction, thereby pushing the cutting elements into the rock formation.
 3. A mining machine according claim 2, wherein each telescopic hydraulic line unit forms a hydraulic channel, wherein each hydraulic channel is hydraulically connected to the one of first hydraulic lines by means of a first hydraulic block having hydraulic channels, and wherein each hydraulic channel is hydraulically connected to the one of second hydraulic lines by means of a second hydraulic block having hydraulic channels.
 4. A mining machine according to claim 1, wherein the mining machine comprises one or more propelling units for propelling the mining machine, and wherein the propelling unit is configured to rest on a floor of a tunnel during the rock excavation.
 5. A mining machine according to claim 1, wherein the mining machine comprises one or more first stabilizing units movable in relation to the machine body, and wherein the first stabilizing unit is configured to engage a roof of the tunnel to secure the mining machine and counteract forces created during the rock excavation.
 6. A mining machine according claim 5, wherein the mining machine comprises one or more second stabilizing units movable in relation to the machine body and configured to engage a floor of the tunnel to secure the mining machine and counteract forces created during the rock excavation.
 7. A mining machine according to claim 5, wherein at least one of the first stabilizing unit and the second stabilizing unit is attached to the machine body.
 8. A mining machine according to claim 1, wherein the hydraulic consumer or one of the hydraulic consumers is attached to the cutting head.
 9. A mining machine according to claim 1, wherein the hydraulic consumer or one of the hydraulic consumers is attached to the holder.
 10. A mining machine according to claim 1, wherein the mining machine comprises one or more hydraulic motors for rotating the cutting head in relation to the holder, the hydraulic motor comprising the hydraulic consumer or one of the hydraulic consumers.
 11. A mining machine according to claim 1, wherein the hydraulic consumer or one of the hydraulic consumers is attached to the thrust unit.
 12. A mining machine according to claim 1, wherein the mining machine comprises one or more guide apparatuses for guiding the thrust unit in relation to the machine body between the retracted position and the extended position, each guide apparatus comprising a guide.
 13. A mining machine according to claim 12, wherein the guide is substantially linear, and wherein the guide apparatus is configured to linearly move the thrust unit in relation to the machine body between the retracted position and the extended position.
 14. A mining machine according to claim 1, wherein the holder is movable in relation to the thrust unit, wherein the mining machine comprises a positioning apparatus for moving and positioning the holder and the cutting head in relation to the thrust unit in a horizontal direction and/or a vertical direction when the propelling unit rests on the floor of the tunnel.
 15. A mining machine according to claim 1, wherein each cutting element comprises a disc-shaped cutter, wherein the cutting head comprises a cutting head frame having a cutter seat for each cutter, and wherein the cutter is seated in the cutter seat and is rotatable in relation to the cutting head frame.
 16. A mining machine according to claim 1, wherein the cutting head has a first side between the outer circumferential surface and an axis of rotation of the cutting head and a second side between the outer circumferential surface and the axis of rotation of the cutting head, wherein the holder comprises a first arm extending at least partly along the first side and holding the cutting head, whereas the second side of the cutting head is without any such arm.
 17. A mining machine according to claim 1, wherein the hydraulic pump is attached to the machine body.
 18. A mining machine according to claim 1, wherein the mining machine comprises a first part and a second part, wherein the first part comprises the cutting head, the holder, the thrust unit and the machine body, wherein the second part comprises the hydraulic pump, and wherein the first and second parts are connectable to one another.
 19. A mining machine according to claim 18, wherein at least one of the first and second the stabilizing units is configured to secure the first part to counteract forces on the first part created during the rock excavation.
 20. A mining machine according to claim 18, wherein the second part comprises control equipment for controlling the mining machine.
 21. A mining machine according to claim 18, wherein the mining machine comprises an operator cabin attached to the second part of the mining machine, and wherein the mining machine is controllable from the operator cabin.
 22. A mining machine according to claim 1, wherein the mining machine is controllable from a remote location.
 23. A mining machine according to claim 1, wherein the mining machine is configured to operate at least partly autonomously.
 24. A method for conveying hydraulic fluid to and from a hydraulic consumer with the aid of a mining machine comprising a machine body, a rotatable cutting head, a holder for holding the rotatable cutting head, a thrust unit attached to the holder, a thrust apparatus for moving the thrust unit in relation to the machine body, wherein a hydraulic line system comprising two telescopic hydraulic line units is comprised in the mining machine, of which each telescopic hydraulic line unit hydraulically connects one of first hydraulic lines attached to the machine body to one of second hydraulic lines attached to the thrust unit and wherein each telescopic hydraulic line unit comprises a first tube and a second tube movable in relation to one another, wherein the first tube is configured to telescope into the second tube, wherein the method comprises: conveying hydraulic fluid from a hydraulic pump to the hydraulic consumer by means of the hydraulic line system and the telescopic hydraulic line units; and conveying hydraulic fluid from the hydraulic consumer to the hydraulic pump by means of the hydraulic line system and the telescopic hydraulic line units.
 25. A method for rock excavation with the aid of a mining machine comprising: a machine body, a rotatable cutting head, a holder for holding the rotatable cutting head, a thrust unit attached to the holder, a thrust apparatus for moving the thrust unit in relation to the machine body, wherein a hydraulic line system comprising two telescopic hydraulic line units is comprised in the mining machine, of which each telescopic hydraulic line unit hydraulically connects one of first hydraulic lines attached to the machine body to one of second hydraulic lines attached to the thrust unit and wherein each telescopic hydraulic line unit comprises a first tube and a second tube movable in relation to one another, wherein the first tube is configured to telescope into the second tube, wherein the method comprises: pushing the thrust unit in a forward direction by means of the thrust apparatus, thereby pushing cutting elements of a cutting head into the rock formation; conveying hydraulic fluid from a hydraulic pump to a hydraulic consumer of the mining machine, which hydraulic consumer is a hydraulic motor for rotating the cutting head in relation to the holder, by means of the hydraulic line system and the telescopic hydraulic line units; conveying hydraulic fluid from the hydraulic consumer to the hydraulic pump by means of the hydraulic line system and the telescopic hydraulic line units; and rotating the cutting head by means of the hydraulic motor. 